Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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Vectorize cell boundaries in GRASS

I need to vectorize the cell boundaries of a raster map and I have forgotten how to do this. For instance, if I have a raster map of a region that is just map=1 with a cell size of 500m, I would ...
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1k views

Where are imported Mosaic Dataset images stored on ArcSDE server?

I am trying to learn more about Mosaic Datasets and specifically how they interact with ArcSDE (SQL Server 2008). I read in How raster data is stored in a geodatabase that "...In the case of the ...
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0answers
335 views

ValueError when reading a raster band as a numpy array

Here's the problem shown in Python shell: In [32]: from osgeo import gdal In [33]: geotiff = '/Users/calvin/work/luc/proj_public/media/GLO ...
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4answers
8k views

Loading a raster into a PostGIS 2.0 database on Windows

I'm trying to figure out how to load a raster into a PostGIS2.0 database (I have asked previous questions on this topic here and here). I am trying to use the raster2pgsql.exe program provided with ...
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2answers
680 views

Extract all pixels of given RGB value and render as MultiPolygons

Given a geotiff image with a colortable in it, what is the easiest way to extract each color as its own "layer or shapefile or multipolygon object"? Specifically, I am looking for a programmatic ...
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4answers
730 views

MapServer rendering at the lowest zoom levels

I am developing a web mapping application based on OpenLayers and using a WMS layer from MapServer (the source data for this layer is stored in PostGIS database) and I am facing the following problem: ...
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98 views

How to delete classes that cover only a small area? [duplicate]

I want to delete pixels that have a small area of classifying in raster and vector images in ArcGis software.
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1answer
2k views

Loading a raster using QGIS into a PostGIS2.0 enabled database

Following on from my attempt to install a postgresql 9.1 db with postgis 2.0 on windows 7, I am trying to figure out how to load a raster. I have successfully loaded a shapefile, and am trying to do ...
5
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1answer
516 views

Creating field with specified slope projecting from 3D polygon?

I am trying to figure out how to create a elevation raster from a known location (3D polygon) that projects at a specified slope (1%) for a specified distance(1-2 km). Does anyone have any idea how ...
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2answers
195 views

Is there a simple way to detect what generation a MrSID file is?

I just found out there are a few types of MrSID files - generations MG2,MG3,MG4. As I have a user which uses Bentley Microstation V8 and apparently can see only some of the generations (and thus I ...
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1answer
643 views

How to convert dbf to raster the short way?

I have got a dbf file and i want make it to raster file but shor way, Look at my long way, 1- First i add my dbf file 2- and i create tin http://i1211.photobucket.com/albums/cc421/mtnkou/2.jpg 3- ...
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How to crop a Raster by Region?

I have created a grid using the point density function in VM. I would like to crop this image to a region created from buffering a polyline feature set. Is this possible? Alternatively I have used the ...
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2answers
1k views

How to convert from GeoTIFF to PNG/JPG and Web Mercator in Java?

I'd like to convert raster image from (geo)tiff to an png/jpg and afterwards if it is necessary ... I'd like to convert the coordinates with help of EPSG-Codes to the OSM/Google Projection(EPSG: ...
5
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1answer
459 views

Is there any plugin for QGIS to calibrate contrast and brightness of a raster layer?

I frequently need to deal with the contrast and brightness of raster layers in QGIS and I miss the tools in ArcGIS for this task. Should there be a plugin already developed for QGIS? If there is, ...
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2answers
3k views

How to create a color ramp in ArcGIS10 where the zero value is represented by white?

I have a simple problem which (to me) seems to be difficult to solve in ArcGIS. The map I plot is a GeoTIFF with emission data. I use a default algorithmic color ramp (rainbow) to do so. Now I would ...
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1answer
5k views

Converting a polygon into a raster using R

I'm trying to convert a shapefile into a raster within R. My approach is to read in the raster as follows: library(rgdal) # Loads SP package by default demo <- readOGR('F:/data/', 'shapefile') # ...
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2answers
2k views

How to build an artificial 'dam' across a river?

I have a DEM. Created all files related to watershed including accumulation, direction, streams etc... I'm stuck creating a dam. I request you to please let me know how to build an artificial 'dam' ...
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1answer
411 views

Perform Multiply (Times) Function on Several Reclassified Rasters Using Python

I have several reclassified rasters (0 = snow cover, 1 = no snow) and I would like to use the multiply function on all rasters that have the same spatial extent. In ArcGIS 10 this function can be ...
2
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1answer
339 views

Search Raster Files from Folder that Have Same Spatial Coordinates Using Python

I have approximately 700 raster files in a single folder and I need to find files that have the same spatial extent and copy to a different folder. The raster files measure daily snow cover and ...
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5answers
8k views

How to perform Raster Reclassification in QGIS?

Is there a way to do reclassify a raster image to Qgis? In Arcgis you can do that in Spatial analyst Tools→Reclass→Reclassify Any ideas?
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3answers
385 views

How can I generate and publish raster images?

I have several hundred groups of data points (in lat/lng format). I want to generate heat maps for each group using kriging or similar interpolations and then display the generated raster images on a ...
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2answers
8k views

Manipulate .asc files in qgis

I have an .asc file and I want to import in QGIS. The standard way to open it is from "add Raster layer" ("import Raster Layer"), there is another way? I know is strange that ask but I need it. And I ...
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0answers
106 views

How can I identify the pixel with the maximum value in a grid? [duplicate]

Possible Duplicate: How to find the locations of the highest values in a raster? How can I identify the pixel with the maximum value in a grid and get its coordinates? Any VBA code please?
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1answer
1k views

Multiple Conditional Reclassification - ArcGIS

This is a question out of curiosity rather than a problem as I am not the most experienced with raster datasets and I wonder if there is a better solution to my current approach. I am trying create a ...
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How to smooth/interpolate a raster in python using GDAL?

This is my first post so please feel free to critique where necessary. Background: I am developing in Python and using GDAL from OSGEO to manipulate and interact with rasters and shapefiles. ...
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3answers
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Export georeferenced image overlay from KML?

How might one export image(s) from image overlays in a KML file to a standard geo-referenced raster format like geotiff? Use case: NASA's Earth Observatory has a time series of the changing Athabasca ...
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1answer
260 views

Looking for US National Grid to Lon/Lat Converter in Python, C, or C++

I see here that there is Fortran source code for going from USNG to lon/lat: http://www.ngs.noaa.gov/PC_PROD/USNG/ Is there some python or C/C++ code that does the same? My understanding that this ...
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1answer
5k views

Raster legend in R: how to colour specific values?

I have an elevation model plotted in R r <- raster("example.dem") plot(r, col = topo.colors(20)) Some of the values are below sea level (0), and I'd like to have those display in red. How can ...
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2answers
2k views

What resampling technique should be used when projecting aerial photos?

I'm doing some time-intensive projecting of aerial photos, and I'm curious - what resampling technique is best to use on aerial photos? In ArcMap, my options are NEAREST, BILINEAR, CUBIC, and ...
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2answers
1k views

Extract the area of a DEM above where 60% of the region lies?

I have a DEM of a mountainous region. I'd like to extract the areas of the DEM above which 60% of the total DEM area lies. So, essentially I'd like to extract the areas representing upper portions of ...
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1answer
2k views

Random sampling of raster using R

Is there a straightforward way of randomly sampling a raster so that the output of the process is a raster? I'm using an example that I found on the r-sig-geo list and I have also tried the ...
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1answer
786 views

Method to shade or overlay a raster map to reflect time of day and ambient light

I have a daytime raster of my study area. I have 20+ counters in the study area that count "stuff" with a timestamp. Using PyEphem I determined the type of ambient light for each collected data ...
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164 views

Can I overlay layers in Dealul Piscului 1970 and WGS84 in QGIS?

I have a 10 Gb ECW file (mosaic of a whole county) that is in Oblique Stereographic projection with Datum: Dealul Piscului 1970. The problem was that no matter the Default CRS for new project was, ...
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1answer
368 views

ArcPy replaceDataSource to an SDE raster catalog error

New to Python! I'm trying to re-path a multitude of rasters currently the workspace is a folder, the intended workspace is a raster catalog in an SDE database - using the replaceDataSource method I'm ...
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2answers
501 views

How to fix a raster with wrong Eastings?

I get an error when trying to warp a tif file in QGIS: ERROR 1: Too many points (35721 out of 35721) failed to transform, unable to compute output bounds. I am using QGIS 1.7.0 Wroclaw with gdal ...
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3answers
747 views

Dealing with bridges and tunnels when modeling raster least cost paths?

I'm currently using ArcGIS 10 Spatial Analyst's Cost Path tool to model pedestrian routes. I have sidewalks, fences, buildings and a ton of pedestrian scale features, all combined into a cost surface ...
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2answers
383 views

Reading multiple grid data with Python and ModelBuilder

How can I read grid data (3 or 5 sources of grids) like slope, soil, cover, etc.? My goal is to build a simulator based on multiple grid data for harvesting decisions.
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Simplify Raster Contours ArcGIS 10

Does anybody know a way to simplify a number of contour polylines derived from a raster dataset? I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
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2answers
492 views

How to add different sized rasters in GDAL so the result is only in the intersected region

I'm writing a Python method that adds two rasters and generates a single raster output. For reasons beyond my control, the extents of the input rasters are different, but they do overlap. Is it ...
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2answers
808 views

Tools/processes that avoid the need for raster to vector converstion?

A "brute force" method of solving GIS problems that involve acquiring values from raster cells and storing them on spatially overlapping vector features is to first convert the raster to a vector. The ...
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1answer
927 views

Workaround for Raster data input in ArcGIS Server Geoprocessing Service

UPDATE I have accomplished the Python script, but only tested in desktop environment, i.e. ArcMap. #Import ArcPy site package module import arcpy from arcpy import env from arcpy import Extent from ...
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4answers
7k views

How can I export raster data from Arcmap to an R *.grd file format?

I want to work with raster data in R, but I have problems exporting my raster dataset from ArcMap. By "export data"/GRID I get a file with an *.aux extension. What I need is *.grd. Can anybody help ...
4
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2answers
328 views

Reproject TM65 to OSGB in ArcGIS

I have a TIFF file in the TM65 (Transverse Mercator) projection, and want to convert it to the OSGB (British National Grid) projection. I'm trying to do this in ArcGIS using the Project Raster tool. ...
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1answer
371 views

How to Create and Rotate Raster Dataset using ArcObjects?

I'm following the "How to create a raster dataset" tutorial: http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#//000100000464000000 The questions are: 1) How can I create ...
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1answer
323 views

Bounding box argument ignored when displaying raster using mapserver

I am trying to display a raster image with Mapserver using different bbox arguments in a mapserv cgi request. I have been trying to specify different bbox arguments to "crop" the raster display, but ...
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1answer
4k views

How to import a raster into PostGIS?

I'm trying to follow the instructions here to load a raster into a PostGIS database: python raster2pgsql.py -s 4269 -I -r *.tif -F myschema.demelevation -o elev.sql I understand that I replace * ...
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2answers
823 views

GeoTIFFs made in GDAL don't have min/max range when loaded in Arc/QGIS

I'm creating some floating point rasters in GDAL with the GeoTIFF driver. When I load the resulting images into QGIS or Arc the default symbology puts the min at -3.40282e38 and max to 3.40282e38, so ...
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2answers
171 views

Distortion of equally sized world tiles

My question is related to this: http://stackoverflow.com/questions/7927863/location-data-format-for-adehabitat-package I have a relational database with 'world tiles'. Each tile has a side length of ...
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1answer
1k views

Conditional reclassification of a raster

I am attempting to do a conditional reclassification of an NLCD land-use raster. I specifically want to reclassify all developed areas (classifications 22,23,24) that are near a road (classification ...
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1answer
571 views

Simple band arithmetic on GDAL virtual rasters (VRT)

I want to calculate the difference of two bands. I have the individual bands stored somewhere, but I was thinking that maybe there's a way of producing a VRT file that is the result of this ...